Rocking curve imaging of high quality sapphire crystals in backscattering geometry

Jafari, A.; Klobes, Benedikt; Sergueev, I.; Hermann, Raphael; Asadchikov, V. E.; Alexeev, P.; Roschin, B. S.; Härtwig, J.; Wille, H.-C.; Chumakov, A. I.; Bessas, D.

doi:10.1063/1.4974106

Journal Article

FZJ-2017-01517

Rocking curve imaging of high quality sapphire crystals in backscattering geometry

Jafari, A.FZJ* ; Sergueev, I. ; Bessas, D. ; Roschin, B. S. ; Asadchikov, V. E. ; Alexeev, P. ; Härtwig, J. ; Chumakov, A. I. ; Wille, H.-C. ; Hermann, R. (Corresponding author)FZJ* ; Klobes, B.

2017
American Inst. of Physics Melville, NY

Journal of applied physics 121(4), 044901 (2017) [10.1063/1.4974106]

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Please use a persistent id in citations: http://hdl.handle.net/2128/16856 doi:10.1063/1.4974106

Abstract: We report on the characterization of high quality sapphire single crystals suitable for high-resolution X-ray optics at high energy. Investigations using rocking curve imaging reveal the crystals to be of uniformly good quality at the level of ∼10−4 in lattice parameter variations, δd/d. However, investigations using backscattering rocking curve imaging with a lattice spacing resolution of δd/d∼5×10−8 show very diverse quality maps for all crystals. Our results highlight nearly ideal areas with an edge length of 0.2–0.5 mm in most crystals, but a comparison of the back reflection peak positions shows that even neighboring ideal areas exhibit a relative difference in the lattice parameters on the order of δd/d=10–20×10−8; this is several times larger than the rocking curve width. Stress-strain analysis suggests that an extremely stringent limit on the strain at a level of ∼100 kPa in the growth process is required in order to produce crystals with large areas of the quality required for X-ray optics at high energy.

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